<template>
    <div>
        <div
            class="mask"
            v-show="isShowSelect"
            @click="isShowSelect = !isShowSelect"
        ></div>
        <el-popover
            placement="bottom-start"
            :width="width"
            trigger="manual"
            v-model="isShowSelect"
            @hide="popoverHide"
        >
            <el-select
                slot="reference"
                ref="select"
                :size="size"
                v-model="selectedData"
                :multiple="multiple"
                :clearable="clearable"
                :collapse-tags="collapseTags"
                @click.native="isShowSelect = !isShowSelect"
                @remove-tag="removeSelectedNodes"
                @clear="removeSelectedNode"
                @change="changeSelectedNodes"
                class="tree-select"
            >
                <el-option
                    v-for="item in options"
                    :key="item.value"
                    :label="item.label"
                    :value="item.value"
                />
            </el-select>
            <el-tree
                class="common-tree"
                ref="tree"
                :style="`width: 100%; ${height}px`"
                :data="data"
                :props="defaultProps"
                :show-checkbox="multiple"
                :node-key="nodeKey"
                :check-strictly="checkStrictly"
                default-expand-all
                :expand-on-click-node="false"
                :check-on-click-node="multiple"
                :highlight-current="true"
                @node-click="handleNodeClick"
                @check-change="handleCheckChange"
            />
        </el-popover>
    </div>
</template>

<script>
export default {
    name: 'tree-select',
    props: {
        // 树结构数据
        data: {
            type: Array,
            default() {
                return []
            }
        },
        defaultProps: {
            type: Object,
            default() {
                return {}
            }
        },
        // 配置是否可多选
        multiple: {
            type: Boolean,
            default() {
                return false
            }
        },
        // 配置是否可清空选择
        clearable: {
            type: Boolean,
            default() {
                return false
            }
        },
        // 配置多选时是否将选中值按文字的形式展示
        collapseTags: {
            type: Boolean,
            default() {
                return false
            }
        },
        nodeKey: {
            type: String,
            default() {
                return 'id'
            }
        },
        // 显示复选框情况下，是否严格遵循父子不互相关联
        checkStrictly: {
            type: Boolean,
            default() {
                return false
            }
        },
        // 默认选中的节点key数组
        checkedKeys: {
            type: Array,
            default() {
                return []
            }
        },
        size: {
            type: String,
            default() {
                return 'small'
            }
        },
        width: {
            type: Number,
            default() {
                return 250
            }
        },
        height: {
            type: Number,
            default() {
                return 300
            }
        }
    },
    watch: {
        isShowSelect(val) {
            console.log(val)
            // 隐藏select自带的下拉框
            this.$refs.select.blur()
        },
        checkedKeys(val) {
            if (!val) return
            this.checkedKeys = val
            this.initCheckedData()
        }
    },
    data() {
        return {
            isShowSelect: false, // 是否显示树状选择器
            options: [],
            selectedData: [], // 选中的节点
            style:
                'width:' + this.width + 'px;' + 'height:' + this.height + 'px;',
            selectStyle: 'width:' + (this.width + 24) + 'px;',
            checkedIds: [],
            checkedData: []
        }
    },
    mounted() {
        this.initCheckedData()
    },
    methods: {
        // 单选时点击tree节点，设置select选项
        setSelectOption(node) {
            let tmpMap = {}
            tmpMap.value = node.key
            tmpMap.label = node.label
            this.options = []
            this.options.push(tmpMap)
            this.selectedData = node.key
        },
        // 单选，选中传进来的节点
        checkSelectedNode(checkedKeys) {
            var item = checkedKeys[0]
            this.$refs.tree.setCurrentKey(item)
            var node = this.$refs.tree.getNode(item)
            this.setSelectOption(node)
        },
        // 多选，勾选上传进来的节点
        checkSelectedNodes(checkedKeys) {
            this.$refs.tree.setCheckedKeys(checkedKeys)
        },
        // 单选，清空选中
        clearSelectedNode() {
            this.$refs.tree.setCurrentKey(null)
        },
        // 多选，清空所有勾选
        clearSelectedNodes() {
            var checkedKeys = this.$refs.tree.getCheckedKeys() // 所有被选中的节点的 key 所组成的数组数据
            for (let i = 0; i < checkedKeys.length; i++) {
                this.$refs.tree.setChecked(checkedKeys[i], false)
            }
        },
        initCheckedData() {
            if (this.multiple) {
                // 多选
                if (this.checkedKeys.length > 0) {
                    this.selectedData = this.checkedKeys
                    this.checkSelectedNodes(this.checkedKeys)
                } else {
                    this.selectedData = ''
                    this.clearSelectedNodes()
                }
            } else {
                // 单选
                if (this.checkedKeys.length > 0) {
                    this.selectedData = this.checkedKeys[0]
                    this.checkSelectedNode(this.checkedKeys)
                } else {
                    this.selectedData = ''
                    this.clearSelectedNode()
                }
            }
        },
        a2b(ls) {
            return ls.map(obj => {
                let result = { id: '', text: '' }
                if (obj.children && obj.children.length > 0) {
                    result.id = obj.value
                    result.text = obj.label
                    result.arr = this.a2b(obj.children)
                    return result
                } else {
                    result.id = obj.value
                    result.text = obj.label
                    return result
                }
            })
        },
        popoverHide() {
            if (this.multiple) {
                this.checkedIds = this.$refs.tree.getCheckedKeys() // 所有被选中的节点的 key 所组成的数组数据
                this.checkedData = this.$refs.tree.getCheckedNodes() // 所有被选中的节点所组成的数组数据
            } else {
                this.checkedIds = this.$refs.tree.getCurrentKey()
                this.checkedData = this.$refs.tree.getCurrentNode()
            }
            this.$emit('checked-change', this.checkedIds, this.checkedData)
        },
        // 单选，节点被点击时的回调,返回被点击的节点数据
        handleNodeClick(data, node) {
            if (!this.multiple) {
                this.setSelectOption(node)
                this.isShowSelect = !this.isShowSelect
                this.$emit('change', this.selectedData)
            }
        },
        // 多选，节点勾选状态发生变化时的回调
        handleCheckChange() {
            var checkedKeys = this.$refs.tree.getCheckedKeys() // 所有被选中的节点的 key 所组成的数组数据
            this.options = checkedKeys.map(item => {
                var node = this.$refs.tree.getNode(item) // 所有被选中的节点对应的node
                let tmpMap = {}
                tmpMap.value = node.key
                tmpMap.label = node.label
                return tmpMap
            })
            this.selectedData = this.options.map(item => {
                return item.value
            })
            this.$emit('change', this.selectedData)
        },
        // 多选,删除任一select选项的回调
        removeSelectedNodes(val) {
            this.$refs.tree.setChecked(val, false)
            var node = this.$refs.tree.getNode(val)
            if (!this.checkStrictly && node.childNodes.length > 0) {
                this.treeToList(node).map(item => {
                    if (item.childNodes.length <= 0) {
                        this.$refs.tree.setChecked(item, false)
                    }
                })
                this.handleCheckChange()
            }
            this.$emit('change', this.selectedData)
        },
        treeToList(tree) {
            var queen = []
            var out = []
            queen = queen.concat(tree)
            while (queen.length) {
                var first = queen.shift()
                if (first.childNodes) {
                    queen = queen.concat(first.childNodes)
                }
                out.push(first)
            }
            return out
        },
        // 单选,清空select输入框的回调
        removeSelectedNode() {
            this.clearSelectedNode()
            this.$emit('change', this.selectedData)
        },
        // 选中的select选项改变的回调
        changeSelectedNodes(selectedData) {
            // 多选,清空select输入框时，清除树勾选
            if (this.multiple && selectedData.length <= 0) {
                this.clearSelectedNodes()
            }
            this.$emit('change', this.selectedData)
        }
    }
}
</script>

<style scoped>
.mask {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 11;
    width: 100%;
    height: 100%;
    opacity: 0;
}
.common-tree {
    overflow: auto;
}
.tree-select {
    z-index: 111;
}
</style>
